This miniboss is a reference to the artist and programmer of Binding of Isaac, Edmund McMillen and Florian Himsl respectively.

The Left Hand trinket is a reference to Edmund McMillen being left handed. It is also likely that it refers to Edmund's tattoo on that hand, which resemble the lines a surgical cut would follow.

He is named "Ultra Pride" because Edmund and Florian consider Pride "their sin", the deadly sin they commit the most.

Ultra Pride is unique in that there is no known "ultra" counterpart for the other deadly sins.

Pride is the sin considered above all others as it was the sin that tempted Satan to rebel against God.

Ultra Pride's familiar uses the same AI as the Babies. The homing tears that it shoots may be a reference to (or the original cause of) the "Psy Baby" bug.

The room ID to spawn Ultra Pride is "us", presumably meaning Ultra Sloth. This implies that Ultra Pride may be coded as a "super" version of Super Sloth. This is also backed up by his SpiderMod entity code spawning Super Sloth unless certain conditions are met. Although, "us" could be referring to Edmund and Florian, as they are the creators of the game, as in "us".